In recent years, storage systems configured with a storage area network (SAN) architecture in which fiber channel switches are used are becoming mainstream. On a SAN, a plurality of severs, a plurality of storage units, and a plurality of other peripheral units are mutually connected through fiber channels. Storage integration, in which data in a plurality of severs is stored together, is carried out through a SAN.
With the SAN, a fiber channel switch called a center witch or director is used. The center switch has a function that is a kernel in data routing. Specifically, the center switch assigns port IDs (PIDs) to devices connected to it. The assigned PIDs are stored in a name server in the center switch. The center switch uses a PID stored in the name server to transfer data received from a device (a server, for example) to a specified device (a storage unit, for example). In addition, the center switch acquires data from a specified device and transfers the acquired data to a device that has requested the data. Since many devices are mutually connected in recent years, a SAN to which a plurality of center switches are connected is often used. From the viewpoint of the fiber switch, a switch that simply performs routing may be connected to a center switch of this type.
Some SANs use a redundant configuration to protect against communication failures. In a conventional technology, for example, a plurality of fiber channel switches are connected to a single device and data transmission routes are duplicated; in this configuration, after a switchover has been made, a state is monitored through broadcasting and a routing table is updated.
When a redundant configuration is used, a center switch with a redundant configuration may be used, that is, elements that implement the functions of the center switch described above are duplicated. In the description that follows, elements that perform routing in a normal state will be referred to as the active side and duplicated elements to which the center switch switches in case of a failure on the active side will be referred to as the standby side.
In the center switch with a redundant configuration, the active side and standby side each have a name server. Even if the name server in the active side goes down, the center switch switches to the standby side and may uses the name server on the standby side to enable routing as on the active side.
Japanese Laid-open Patent Publication No. 2008-242872 is an example of related art.
If, for example, failures occur on both the active side and standby side, device information stored in the name servers are deleted and address resolution is disabled. This suppresses the center switch, in which both the active side and standby side caused a failure, from carrying out routing. Accordingly, for example, the center switch may no longer route data to a device connected to the center switch.
Even if the conventional technology in which monitoring is performed through broadcasting after a switchover has been made is used, when a switch with a redundant configuration causes failures in the active side and standby side, it is suppressed to route data to devices connected to only the switch.